Power amplifiers receive an input signal of low power and, using an electronic circuit, amplify the signal to higher power. This high power signal may then for example, be used to drive a transmitter or speaker.
Using present technology, a circuit which accomplishes this task includes components that generate substantial amounts of heat, and components that do not generate large amounts of heat.
The substantially heat producing components are placed in contact with a highly thermally conductive heat sink, which dissipates the excess thermal energy, thereby preventing the components from overheating.
A power amplifier, thus, must accomplish two goals: the circuit must be completed electrically and the heat generating components must be attached to a heat sink.
Amplifier designs of the prior art accomplish these goals in one of two ways: the first is typically used when the heat dissipation requirements are moderate. With this design, all components are inserted into a printed circuit board. Electrical connections are made by the traces of the printed circuit board. The heat sink is then mounted directly to the heat producing components. Heat dissipation is limited because the end product's chassis, which mechanically protects the circuit board, also encloses the heat sink. A window can be cut out from the chassis to expose the heat sink to the external environment, but the desired mechanical isolation of the printed circuit board is compromised.
The second prior art design mechanically separates the substantially heat producing devices from the remaining components. The heat producing components are mounted to the heat sink, which is typically mounted so that a significant amount of its surface area is external to the chassis compartment. The rest of the circuit is placed on printed circuit board. The electrical connections are completed by wires with connectors running between the printed circuit board and the heat producing devices. The principle disadvantages of this approach are the cost and complication added by the wiring and the physical separation of related components, which can induce noise, signal degradation, etc.
Desirable features of a power amplifier include: ease of production, large heat dissipation capacity, immunity to mechanical stress, minimized use of connectors and wiring, and ease of maintenance.
The invention finds advantage in its ability to satisfy the above stated design objectives, among others.